Autophagy-inhibiting biomimetic nanodrugs enhance photothermal therapy and boost antitumor immunity

The instinctive protective stress responses of tumor cells hamper the low-temperature photothermal therapy (LTPTT), resulting in tumor recurrence and metastasis. The rapid blood clearance and low-efficiency tumor enrichment of nanomedicines...

Small-Sized Co-Polymers for Targeted Delivery of Multiple Imaging and Therapeutic Agents

Research has increasingly focused on the delivery of high, often excessive amounts of drugs, neglecting negative aspects of the carrier’s physical preconditions and biocompatibility. Among them, little attention has been paid to “small but beautiful” design of vehicle and multiple cargo to achieve effortless targeted delivery into deep tissue. The design of small biopolymers for deep tissue targeted delivery of multiple imaging agents and therapeutics (mini-nano carriers) emphasizes linear flexible polymer platforms with a hydrodynamic diameter of 4 nm to 10 nm, geometrically favoring dynamic juxtaposition of ligands to host receptors, and economic drug content. Platforms of biodegradable, non-toxic poly(β-l-malic acid) of this size carrying multiple chemically bound, optionally nature-derived or synthetic affinity peptides and drugs for a variety of purposes are described in this review with specific examples. The size, shape, and multiple attachments to membrane sites accelerate vascular escape and fast blood clearance, as well as the increase in medical treatment and contrasts for tissue imaging. High affinity antibodies routinely considered for targeting, such as the brain through the blood–brain barrier (BBB), are replaced by moderate affinity binding peptides (vectors), which penetrate at high influxes not achievable by antibodies.

Early cisternal fibrinolysis is more effective than rescue spasmolysis for the prevention of delayed infarction after subarachnoid haemorrhage

BackgroundTo compare the efficacy of two different concepts of cisternal therapy—PREVENTIVE fibrinolysis plus on-demand spasmolysis versus RESCUE spasmolysis—for the prevention of cerebral vasospasm (CVS) and delayed cerebral infarction (DCI) in patients with aneurysmal subarachnoid haemorrhage (aSAH).MethodsRetrospective analysis of 84 aSAH patients selected for cisternal therapy for DCI prevention. 66 high-risk patients received PREVENTIVE cisternal therapy to enhance blood clearance. Either stereotactic catheter ventriculocisternostomy (STX-VCS) or intraoperative placement of a cisterno-ventriculostomy catheter (CVC), followed by fibrinolytic cisternal lavage using urokinase was performed. In case of vasospasm, nimodipine was applied intrathecally. 22 low-risk patients who developed CVS against expectations were selected for STX-VCS as RESCUE intervention for cisternal spasmolysis with nimodipine. Rates of DCI and mean flow velocities of daily transcranial Doppler (TCD) ultrasonographies were evaluated.ResultsDespite a higher prespecified DCI risk, patients selected for PREVENTIVE intervention primarily aiming at blood clearance had a lower DCI rate compared with patients selected for intrathecal spasmolysis as a RESCUE therapy (11.3% vs 18.2%). After intrathecal treatment onset, CVS (TCD>160 cm/s) occurred in 45% of patients with PREVENTIVE and 77% of patients with RESCUE therapy (p=0.013). A stronger response of CVS to intrathecal nimodipine was observed in patients with PREVENTIVE intervention as the mean CVS duration after start of intrathecal nimodipine was 3.2 days compared with 5.8 days in patients with RESCUE therapy (p=0.026).ConclusionsPREVENTIVE cisternal therapy directed at blood clearance is more effective for the prevention of CVS and delayed infarction compared with cisternal RESCUE spasmolysis.Trial registration numberDRKS00016532.

The Scavenger Function of Liver Sinusoidal Endothelial Cells in Health and Disease

The aim of this review is to give an outline of the blood clearance function of the liver sinusoidal endothelial cells (LSECs) in health and disease. Lining the hundreds of millions of hepatic sinusoids in the human liver the LSECs are perfectly located to survey the constituents of the blood. These cells are equipped with high-affinity receptors and an intracellular vesicle transport apparatus, enabling a remarkably efficient machinery for removal of large molecules and nanoparticles from the blood, thus contributing importantly to maintain blood and tissue homeostasis. We describe here central aspects of LSEC signature receptors that enable the cells to recognize and internalize blood-borne waste macromolecules at great speed and high capacity. Notably, this blood clearance system is a silent process, in the sense that it usually neither requires or elicits cell activation or immune responses. Most of our knowledge about LSECs arises from studies in animals, of which mouse and rat make up the great majority, and some species differences relevant for extrapolating from animal models to human are discussed. In the last part of the review, we discuss comparative aspects of the LSEC scavenger functions and specialized scavenger endothelial cells (SECs) in other vascular beds and in different vertebrate classes. In conclusion, the activity of LSECs and other SECs prevent exposure of a great number of waste products to the immune system, and molecules with noxious biological activities are effectively “silenced” by the rapid clearance in LSECs. An undesired consequence of this avid scavenging system is unwanted uptake of nanomedicines and biologics in the cells. As the development of this new generation of therapeutics evolves, there will be a sharp increase in the need to understand the clearance function of LSECs in health and disease. There is still a significant knowledge gap in how the LSEC clearance function is affected in liver disease.

Improved Radiolytic Stability of a 68Ga-labelled Collagelin Analogue for the Imaging of Fibrosis

There is an unmet medical need for non-invasive, sensitive, and quantitative methods for the assessment of fibrosis. Herein, an improved collagelin analogue labelled with gallium-68 for use with positron emission tomography (PET) is presented. A cyclic peptide, c[CPGRVNleHGLHLGDDEGPC], was synthesized by solid-phase peptide synthesis, conjugated to 2-(4,7-bis(2-(tert-butoxy)-2-oxoethyl)-1,4,7-triazonan-1-yl)acetic acid, and labelled with gallium-68. High performance liquid chromatography (HPLC) was used for the quality and stability assessment of the collagelin analogue. Non-specific organ distribution, blood clearance, and excretion rates were investigated in healthy mice and rats using ex vivo organ distribution analysis and dynamic in vivo PET/CT. Mice with carbon tetrachloride (CCl4) induced liver fibrosis were used for the investigation of specific binding via in vitro frozen section autoradiography, ex vivo organ distribution, and in vivo PET/CT. A non-decay corrected radiochemical yield (48 ± 6%) of [68Ga]Ga-NOTA-PEG2-c[CPGRVNleHGLHLGDDEGPC] ([68Ga]Ga-NO2A-[Nle13]-Col) with a radiochemical purity of 98 ± 2% was achieved without radical scavengers. The 68Ga-labelling was regioselective and stable at ambient temperature for at least 3 h. The autoradiography of the cryosections of fibrotic mouse liver tissue demonstrated a distinct heterogeneous radioactivity uptake that correlated with the fibrosis scores estimated after Sirius Red staining. The blood clearance and tissue washout from the [68Ga]Ga-NO2A-[Nle13]-Col was fast in both normal and diseased mice. Dosimetry investigation in rats indicated the possibility for 4–5 PET/CT examinations per year. Radiolytic stability of the collagelin analogue was achieved by the substitution of methionine with norleucine amino acid residue without a deterioration of its binding capability. [68Ga]Ga-NO2A-[Nle13]-Col demonstrated a safe dosimetry profile suitable for repeated scanning.

Association of cabozantinib residual concentration (Ctrough) and blood clearance (Cl/F) with toxicity (tox) and progressive disease (PD) in metastatic renal cell carcinoma (mRCC) patients (pts): Results from a monocentric pharmacokinetics (PK) study.

292 Background: Cabozantinib is a TKI with a substantial efficacy in mRCC. It is associated with a relevant tox leading frequent dose modifications (DM) or drug discontinuations (DD). While an exposure/safety relation has been demonstrated for this drug, an exposure/efficacy relation is still unknown. Cl/F is a measure of elimination of a drug from blood or plasma and lower Cl/F of cabozantinib has been previously associated with increased DM rate in mRCC. Methods: We performed a monocentric PK (INDS MR 5612140520) study in patients with mRCC. Blood draw for assessment of cabozantinib PK was performed at least 8 hours from the last drug dose. Ctrough was estimated with the following equation: Ctrough=Cmeas*0,5DI-24/t1/2. Ctrough and Cl/F were compared in patients with or without a relevant tox and in PD pts vs SD/PR pts. Relevant tox was defined either as G3-4 tox or G2 tox leading to DM or DD. Differences in Ctrough and CL were assessed between the groups with Mann Withney U test. Results: From 01.10.19 to 31.08.20 66 pts were included in this analysis. Twenty one relevant tox and 29 PD were observed. Ctrough was higher in pts experiencing relevant tox than in those who did not: 624,6 ng/ml (IQR 494-1030,2 ng/ml) vs 505,2 ng/ml (IQR 329,2-910,2), p0.012. Conversely Cl/F was lower in relevant tox vs not tox1,85 l/h (IQR 1,4-2,2 l/h) vs 2.27 l/h (IQR 1,7-3,2), p 0.024. In PD pts, Ctrough was lower than in SD/PR pts: 419ng/ml (IQR 317,2 -549,1 ng/ml) vs 554 ng/ml (IQR 416,9-795,6), p 0.0105, while Cl/F was higher in PD patients: 2,6 l/h (IQR 2,14-3,44 l/h) vs SD/PR patients 1.9 l/h (1,930 l/h;IQR 1,35-2,53 l/h); p= 0.011. Time from day cycle 1 to PK blood draw was significatively longer in non-tox pts and numerically longer in PD pts, which have the lowest Ctrough and the highest Cl/F. Conclusions: Cabozantinib toxicity is associated to a higher Ctrough and a lower Cl/F. Cabozantinib PD is associated to a lower Ctrough and a higher Cl/F. Cl/F should be assessed alongside with Ctrough in Cabozantinib PK blood test; Ctrough may decrease and conversely Cl/F may increase with time on treatment. [Table: see text]